The tail fins on existing projectiles cause a significant percentage of the overall aerodynamic drag on the projectiles during flight. Some of the current tail fin designs are adapted to move the fins from a stored position to a deployed position. The structures that are associated with moving the fins from a stored position to a deployed position are usually a large source of separated or re-circulated air flow around the fins (i.e., unwanted drag).
Another drawback with existing tail fin designs is that the locking mechanism often fails to capture the fin in the deployed position in certain environments. In addition, there is commonly excessive free play within the fin when the fin is in a locked and deployed position.
The drawbacks that are associated with the existing structures which move the fins from a stored position to a deployed position could be overcome by developing a fin that does not generate undesirable air flow when the fin is in the deployed condition. Reducing undesirable air flow over the tail fin would dramatically reduce the drag of the tail and increase the overall range of the vehicle. It would also be desirable if the fins were able to lock securely in the deployed position in any environment that the projectile might be exposed to during use.